Present United States television receivers display an image with an aspect ratio of 4:3. This standard was developed by The National Television System Committee (NTSC). The aspect ratio developed for use in motion pictures is 16:9, and presently, the industry is working to produce a television transmission and reception system compatible with an aspect ratio of 16:9.
The present NTSC system also uses a scanned image that is interlaced. An interlaced scan has well-known shortcomings that have been addressed with systems such as the High Definition Broadcast (HDTV) System, but most HDTV signals cannot be used by present NTSC television receivers. Also, in some proposed systems NTSC television signals cannot be displayed on HDTV receivers.